Why You Shouldn't Upload an MP3
MP3 files have already lost quality. Mastering a lossy file is like enhancing a blurry photo - you can't recover what's gone.
MP3 files have already lost quality. Mastering a lossy file is like enhancing a blurry photo - you can't recover what's gone.
When you convert audio to MP3, a compression algorithm permanently removes frequencies and details it considers "less important." This process is irreversible - once those frequencies are gone, no software can bring them back.
What you lose specifically High frequencies - cut above ~16 kHz at 128 kbps (320 kbps keeps content up to ~20 kHz) Transient detail - kick and snare attacks get softened Stereo image depth - spatial information is reduced Useful headroom for mastering - less room to work with
The Photocopy Analogy Imagine photocopying a document. The 1st copy looks almost identical. The 2nd copy loses sharpness. The 3rd copy becomes hard to read. MP3 compression works the same way - and mastering a compressed file adds another generation of loss on top.
Feature | WAV / FLAC | MP3 320kbps | MP3 128kbps Frequency range | 20Hz - 22kHz | Cutoff ~20kHz | Cutoff ~16kHz Transient detail | ✓ Fully preserved | ⚠ Softened | ✗ Very softened Stereo image | ✓ Full | ⚠ Reduced | ✗ Limited Mastering quality | ✓ Optimal | ⚠ Good | ✗ Low ceiling
Tip: LoudCraft automatically detects MP3 input and recommends uploading lossless. You'll still get a good result with MP3, but WAV or FLAC will always sound better. If your DAW only exports MP3, it's time to upgrade.
Key takeaway: Always export from your DAW as WAV or FLAC. If MP3 is all you have, LoudCraft will still work - but the quality ceiling is already set.